Flexible and expansible band



March 23, 1954 G BERGH ET AL 2,672,738

FLEXIBLE AND EXPANSIBLE BAND Filed 001;. 31, 1951 INVENTORS GEORGE G.BERGH BY ROBERT G. BERGH ATTORNEYS Patented Mar. 23, 1954 2,672,738FLEXIBLE AND EXPANSIBLE BAND George Bergh and Robert Mass., assignors toBergh Bros. 00., Inc.,

Falls,

G. Bergh, Attleboro Attleboro Falls, Mass., a corporation ofMassachusetts Application October 31, 1951, Serial No.

4 Claims.

This invention relates to flexible and expansible bands, and moreparticularly to expansible metalselves.

The principal object of vide an expansible metallic band being capableof of greater than 100% bands have had numerous drawbacks. In the firstplace, previously employed bands capable of greater than 100% expansionwhen expanded have exhibited large complicated and expensive inmanufacture. Also in the instances where greater than 100% expansion wasattempted, the construction has been complicated and prone to failure.

Therefore, among the objects of our invention is to provide a greaterthan 100% expansion band which will not pinch the skin, which will berelatively simple in construction and not prone to failure.

In the accomplishment of these and other objects of our invention,flanged strips of metal and wind them around a mandrel having the crosssectional shape desired for the finished product.

In between the outer and inner strips two further strips having ashallow H cross section are provided with the outturned and inturnedmarginal flanges at each side.

' the wrapped strips in A further feature of our invention is that theupstanding flange portions of the intermediate strips tend to supportthe skin of a user in the area of the gap between the expanding elementsof the band, and thus when the band contracts the tendency of the handto pinch the skin of the user is substantially reduced.

A further feature of our invention is that the innermost strip may beprewrapped in a totally fully contracted position.

Further objects and features of our invention will best he understoodand appreciated from the following detailed description of a preferredembodiment thereof, selected for purposes of illustration and shown inthe accompanying drawings in which:

Fig. 1 is a View in perspective of a typically wound section of the bandof our invention;

Fig. 2 is a view in side elevation with a portion broken open to showthe detailed construction of cross section; and

Fig. :3 is a crosssectional view of one layer of the band in theexpanded condition.

In the preferred embodiment herein shown the band is made of berylliumcopper and includes in its general organization an innermost strip H1wound around a mandrel (not shown) to form a shallow oval shape. At eachedge of the strip Ill an outturned marginal flange I2 is provided. Im-.mediately outwardly from the strips it two intermediate strips M arewound. These intermediate strips I4 are constructed in a shallow H crosssection and have marginal flanges I 6 which both extend inwardly andoutwardly from the strips 14. The strips 14 lie directly upon strip in,being supported at their point of adjacency in the middle by their ownflanges seen that the substantially right-hand flange 20 of the outerstrip I 8. Also the left-hand flange 12 of the inner strip Ill comes upagainst the right-hand flange l6 of the intermediate strip 14. Thissequence carries forward throughout the band, and it will be seen thatin the preferred embodiment herein shown, the expansion is'-rough=ly-150I With regardto wrapping the elements previous ly described, it shouldbe noted that the flanges l2, l6 and axis of the band itself, andtherefore, will be perpendicular to the mandrel about which the stripsare initially wound, Thus the flanges do not have a tendency to collapseduringthew-rapping stage. It will also be notedthat theilanges l2, l8and 2%] support the various strips in parallel relationship to thegeneral axis ofv the and provide a central support for the mid-areas ofstrips H] and it when in the contracted po: sition. This insures auniform and accurate formation of the curves of each stripand preventsthe--development of unwanted ,concavities across the middles of strips10 and I8.. During expansion as-illustrated in Fig. 3, the centers-ofvstrips .l0.and..l8 are no. longer supported byflanges l6 and alsotheintermediate stripsv 14 are only supported at one end and on oppositesides. This condition,..no..doubt, would .cause collapsing and buckling,if thestrips were woundin such. an expanded. relationship, butsince-theyare wound while. the band .is fully contracted, they receivetheirupermanent set in. the parallel relationship shown inWFig; 2, .andtherefore, do not collapse when expanded.

With further reference to Fig.3; it will be seen that when. theband isin .the expanded condition the outturned, portionsof flanges l6 extendinto the .gap. between outer strips l8 and thereby help holdflthe skinof3auser outwardly from. the gap and tend to minimize the pinching effectcaused by contraction of the band.

The flanges l2, l6 and 20 arranged'to minimize jamming of the band.itself- Thus, it will. be seen that if the outturned portions offlanges I6 were missing, the depend ing flanges ,Zll might .drop intothe gap, between the two strips l4- Such would also be true with respectto flanges 12 of strip Win the eventithat the depending elements offlanges it were missing:

In most uses the band of our invention will be disposed in a curved orcircular position as for a wristband, off-necklace, and therefore, theouter edge in thecurved position will continuously eX-' ert acontractingforce on the entire band. How'- ever; even whenthe band is used in aperfectly flat-condition, it. may bepreloaded to assure fullcontraction. This may be done'by first winding strip lwon' the mandrelwith'the edge flanges l2 o'fz'eachsuccessive wind abutting against thenext succeedingedgeflange l2. Thereafter the inner strip! 0 may beslightly expanded to permit winding'theintermediate strips-l4 thereonwith-the depending-portions of flanges I6 fitting between the adjacentoutturned flanges When this-is done-it will be'seen that the entireband-will have a slight preloaded spring tension urging the band towardcontracted position.

It should be noted that the band ofour in-- vention is adaptable formany uses including ornamental uses related to jewelry, as Well asnumenus-functional uses such as lap robe straps 20 are all perpendicularto the general band.

are also particularly 12 of the strip ID;

" both inturned and in automobiles, baggage handles and even certainother uses wherein the hollow central portion of the band itself isemployed. Of course, the oval cross section herein shown has theadvantage of strongly resisting unwrapping of the band by twisting.However, it will be understood that theba-nd could be made=in-circularformwithout substantial disadvantage and would beequally strong providedboth of its ends were securely anchored against unwrapping.

Since numerous minor variations of this preferredembodi'ment of ourinvention will now be apparent ..to those skilled in the art, it is notintended to confine the invention to the exact form hereinshowm butrather to limit it in terms of the appended claims:

Having thus described and disclosed a preferred embodiment of ourinvention, what we claim as new and desire to secure by Letters Patentis:

l. A flexible and expansible band of the type wherein spring .metalstrips are ,helically' wound and, are provided. with interlockingflanges,.,comprising, an inner strip, outturned marginal flanges on saidinner strip, a pair of intermediate strips, outturned marginal flangeson each-said intermediate strip, an outer strip, .inturned marginalflanges on said outer strip, said stripsbeing wound. with the successiveintermediate stripslying adjacent and contiguous toeach other andoverlying successive inner strips. in pairs, the marginal flanges of.said i'nnerstrips extending outwardly between the inturned flanges ofeach pair of intermediate,stripsthereby slidably interlocking them. intopairs, and. the outer strips sli-dably interlocking .successivepairsofintermediate strip-swith one inturned outer strip extending. inwardlybetween turned flanges of an pair and the other inturned flange .of saidouter strip extending inwardlylbetween the outturned the outflanges ofthe adjacent inner stripof the next.

succeedinglpair.

2. The flexible. and expansible.banddeflnedin claim 1 furthercharacterized by the said flanges on the inner and outer. strips beingof equal height, and the said flangeson. the intermediate stripsextending both inwardly. and outwardly. therefrom by an amount equal tothe height of.

the flanges on the. inner and outer strips, where.- by said flanges willsupport said strips against channeling and collapsing.

3. The flexible and.expansiblebanddefinedin.

claim..2. further characterized by all said flanges.

being at right .angles to all said strips, and. all, of said stripsbeing arranged crosssectionally parallel to the axis of said band.

4.. The flexible and .expansible banddefinedin claim ing a crosssectional, contour in whichthe widest dimension is substantially greaterthan the nare rowestdimension.

GEORGE G. BERGH: ROBERT G. BERGH;

References Cited in" the file of this patent- UNITED STATES PATENTSNumber Name Date 501,815 Aitchison etral. July 18, 1893' 1,279,852Eklund- Sept. 24.1918- 2,51'7,0l1 Meyers Aug. 1, .1950

flange of the intermediate strip of; one.

.3 further-characterized by said band hav

